How do you find the vertex and intercepts for y = -2(x -1)^2 + 3?

1 Answer
May 7, 2018

"see explanation"

Explanation:

"the equation of a parabola in "color(blue)"vertex form" is.

color(red)(bar(ul(|color(white)(2/2)color(black)(y=a(x-h)^2+k)color(white)(2/2)|)))

"where "(h,k)" are the coordinates of the vertex and a"
"is a multiplier"

y=-2(x-1)^2+3" is in vertex form"

"with "h=1" and "k=3

rArrcolor(magenta)"vertex "=(1,3)

"to find the intercepts"

• " let x = 0, in the equation for y-intercept"

• " let y= 0, in the equation for x-intercepts"

x=0rArry=-2(-1)^2+3=1larrcolor(red)"y-intercept"

y=0rArr-2(x-1)^2+3=0

"subtract 3 from both sides"

rArr-2(x-1)^2=-3

"divide both sides by "-2

rArr(x-1)^2=3/2

color(blue)"take the square root of both sides"

sqrt((x-1)^2)=+-sqrt(3/2)larrcolor(blue)"note plus or minus"

rArrx-1=+-sqrt3/sqrt2=+-1/2sqrt6

"add 1 to both sides"

rArrx=1+-1/2sqrt6larrcolor(red)"exact solutions"

x~~-0.22" to 2 dec. places ",x~~2.22larrcolor(red)"x-intercepts"